By ALLEN SALKIN

Published: February 11, 2007

A NICE glass of beer can be a wonderful thing, something to kindle a warm feeling in the belly, a general sense of well-being and kinship with one's fellow humans, and to act as a lubricant to conversation. Yes, beer, as presented in advertisements of yesteryear like L?br?s ''Here's to good friends,'' can be nice.

But you'd never know it from a new crop of campaigns for America's top-selling beers, including last week's Super Bowl showcases, singled out for praise by advertising experts for their guffaw-generating potency.

Call them ''Kill your good friends'' ads. One spot for Bud Light, the top-selling beer in the United States, shows a game of rock, paper, scissors to decide who gets the last bottle. One fellow bashes his chum with an actual rock. Other party guests step past the loser sprawled on the lawn in a display of callousness that seems suited more to a crack den.

''Always worth it,'' the on-screen slogan informs.

A Coors Light commercial shows two tuxedoed men at a wedding declining Champagne with a ''yuck.'' One reveals to the other a case of beer under the table. The only problem is they need ice, which they obtain from a life-size ice sculpture of the just-married couple by hacking off the bride's head with a dinner fork.

America's largest brewers are still producing the more benign ads. But, reduced to relying on their light beers for profit and facing general eroding market share to hard liquor and imports, they are also introducing a new underlying theme: anything that delays a man's beer drinking is bad and must be eradicated, be it women, best friends, jobs, pets or children. In other words, whatever you have to do to get more beer, do it as quickly as possible.

The brewers describe their thinking differently.

Jenny Volanakis, a spokeswoman for Coors Brewing Company, said the wedding ad was not misogynistic. ''Weddings are a beer-drinking occasion,'' she said, ''and we were simply trying to take a humorous slant.''

Bob Lacky, executive vice president for global industry development at Anheuser-Busch, also referred to the humor, not the content, of the ''Always worth it'' campaign, in replying to a question about what the slogan meant.

''The campaign,'' he wrote in an e-mail message, ''features humorous situations depicting people going to great lengths to get an ice-cold Bud Light.''

Other products also nibble at the edges of a pessimistic approach. A recent Hummer ad showed an astronomer trading his economy car for a gas-guzzling H2 once he realizes a giant meteor is on a collision course to hit Earth. It's the end of the world as we know it, one is told, so better do what you can to feel fine. The tagline is, ''We're not saying, we're just saying.''

At first glance, the ads, like a Will Ferrell comedy, seem to be mining the wry I-am-making-fun-of-myself-making-a-joke-even-as-I-make-a-joke brand of humor. They also benefit from expectations that beer commercials are lighthearted.

But now the humor can be dark and even scary. In one Bud Light ad, a driver picks up a hitchhiker with an ax, despite his girlfriend's horrified protests, because the hitcher also has some Bud Light. Again: ''Always worth it,'' whether potential rape or ax murder.

Gone from this breed of ad are characters like ''the twins,'' a pair of bikini-clad sex bombs featured in Coors Light spots a few years back, and other images that suggest beer can help its core audience, men in their early 20s, score hot young women. This was the ''Drink beer, get girl'' school of advertising.

A 1996 study of adolescents' responses to beer ads by the Center for Science in the Public Interest found that ''advertisements typically associate beer consumption with sexual prowess, athleticism and social success, and show characters having fun in different social settings.'' As for ads set on the beach, the report noted that respondents associated qualities like ''good-looking,'' ''popular,'' ''cool,'' ''fun'' and ''happy'' with characters in the beach ads 10 times more than negative qualities like ''sad,'' ''mean,'' ''threatening'' or ''loud.'' In the new breed of ads, getting the girl is out.

''It's about getting the beer,'' said George Hacker, director of the alcohol policies project at the Center for Science in the Public Interest, who participated in the 1996 study and regards the situation as radically changed. ''Nothing is nearly as important as the beer.''

Hard drinkers are more important than ever to the large brewers. Sales of standard Budweiser peaked at 50 million barrels in 1988 and dropped to 26 million barrels in 2006. Likewise, regular Coors sells half what it did at its peak, said Benj Steinman, publisher of Beer Marketer's Insights, a trade publication.

This has left hope concentrated in the light beers. The top five best-selling beers in the United States are, in order, Bud Light, Budweiser, Miller Lite, Coors Light and Natural Light, Mr. Steinman said. But with sales for light beers basically flat in the last few years, the big brewers ''are really struggling for what's their identity going forward,'' Mr. Steinman said. (Miller Lite sales were down half a percent in 2006. Bud Light, which had three Super Bowl spots, was up 4 percent.)

Despite gestures brewers make to responsible drinking, 10 percent of beer drinkers drink 43 percent of reported beer consumption, according to a 1999 study in the Journal of Studies on Alcohol. Eric Shepard, executive editor of Alcohol Issues Insights, said the study was the most recent he was aware of, and using its figures estimated that a core drinker would be consuming nearly a gallon of beer a day.

Forging an identity as sellers of oblivion to those who want it appears to be the strategy of the moment.

Ms. Volanakis of Coors said the company had no intention of changing the strategy of its current ''Rocky Mountain cold refreshment'' campaign, which includes harder-edged ads like the one with the ice-bride decapitation. Coors Light has had six consecutive quarters of growth.

''We know this campaign is working,'' she said. ''We see it in the numbers and from our own consumer testing. It has really been resonating.''

Photos: Dark Beer -- In a recent spate of ads, social drinking betrays an odd new underbelly of selfish, antisocial behavior. Above, a Bud Light drinker wields a six-pack, and an ax. Another Bud Light spot, left, features a face-slapping session among business colleagues. (Photo by Anheuser Busch)